<!DOCTYPE html>
<html>
<head>
<style>
#myDIV {
  border: 1px solid black;
  margin: 5px;
}
</style>
</head>
<body>

<div id="myDIV">
  <h2 class="example">A heading with class="example" in div</h2>
  <p class="example">A paragraph with class="example" in div.</p> 
</div>

<p>Click the button to add a background color to the first element in DIV with class="example" (index 0).</p>

<button onclick="myFunction()">Try it</button>

<p><strong>Note:</strong> The querySelectorAll() method is not supported in Internet Explorer 8 and earlier versions.</p>

<script>
function myFunction() {
  var x = document.getElementById("myDIV").querySelectorAll(".example");
  x[1].innerText = "red";
}
</script>

</body>
</html>
